Supporting means for arc-lamp electrodes.



l. C. OHNSTAD. SVUPPORNNG MEANS FOR ARC LAMP ELECTRODES.

'Patented-Aug. 7, 1917.

APPLICATION FILED lULY 9|-9-13- W'trwesses l Inventor" j' Joh CiytaciA DE ZZ@ w His yfl'tofrwel UNITED STATES PATENT OFFICE.

JOHN C. OHNSTAD, OF FORT MONROE, VIRGINIA, A-SSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SUPPORTING MEANS FOR ARC-LAMP ELECTRODES.

Specification of Letters Patent.

Patented Aug. '7, 1917.

Application filed July 9, 1913, Serial No. 778,013.

7 10 LU lwhom t may concern.'

Be it known that I, JOHN C. OHNs'rAD, a citizen of the United States, residing at Fort Monroe, county of Elizabeth City, State of Virginia, have invented certain new and useful Improvements in Supporting Means for Are-Lamp Electrodes, of which the following is a specification.

My invention has reference to an improvement in arc lamps and more particularly to an improved mechanism by which the electrodes are made to burn away evenly.

In the operation of arc lamps, and more especially in the operation of searchlights, to which my invention is particularly applicable, the arc tends to persist between any two points on .the arcing faces of the electrodes on which it may happen to be established, with the result that those portions of the arcing ends of the electrodes between which the arc is formed are burned away more rapidly than the remaining por tions of said ends, thus leaving the arcing faces uneven. This condition continues until the arc becomes excessively long, when it suddenly shifts to points which are more proximate, whereby the arc is greatly shorteued, the current correspondingly increased and the light is made unsteady. This is very objectionable, particularly in searchlights, where an especially steady light is desirable. My invention overcomes these. diliculties by providing a novel means by which one of the electrodes may be rotated about its own axis combined with means for turning or swinging the electrode in one or more planes about axes which are perpendicular to the axis of the electrode.

For a fuller understanding of my invenn tion, reference may be had to the accompanying drawings, which show the best form of my invention now known to me, and in which Figure 1 is a side elevation partially in section; Fig. 2 is a view at right angles to Fig. 1; and Fig. 3 is a side elevation showing the support for the searchlight and the exterior appearance of the same.

In the drawings, 1 is the base (see Fig. 3) on which the searchlight is mounted. The base is provided with upwardly projecting standards 2 within which the searchlight, the casing of which is represented by the reference numeral 3, is mounted in the usual manner on trunn-ions, as indicated.

Referring now to Figs. 1 and 2, 4, 11 are the standards which support one of the electrodes. It will be understood that these are mounted upon a suitable carriage, and that the other electrode also is mounted on a carriage and that suitable mechanism is provided for moving the two electrodes together or apart in accordance with the requirements of the are. The mechanism by which such rectilinear, axial movement of the electrodes is effected is now well known in the art and I have not, therefore, illustrated the same.

A cross arm or bar 5 is secured to the upper ends of the standards 4, This bar is in fact a frame composed of two parallel plates connected at one point by a web 5', so that it is bifurcated at either end, two such bifurcated ends being turned upwardly at 6, while the other bifurcated portions are turned downwardly at 7 at the other end. The bar is provided at the upper side with two outwardly extending flanges 5a which are seated upon the upper ends of the standards 4. A supporting arm 8 for the electrode is fixed on a shaft 9, which is j ournaled in the bifurcated ends 6 of the cross bar This shaft may be rotated by a bar 10, which extends without the casing of the searchlight and which is connected to the shaft by a universal joint 11. One end of the arm 8 is provided with a downwardly projecting bracket 12 provided at its lower end with a laterally extending pin 13. A shaft 14 is journaled in the downwardly extending ends 7 of the cross-arm 5, and upon this shaft is mounted a disk 15, which is provided on the face toward the pin 13 with a spiral groove 16. The shaft 14 may be rotated by a bar 17 which also extends without the casing and which is connected to the shaft 14: by a universal joint 18. The pin 13 engages the spiral groove 16 of the disk 15, and, by the rotation of the disk, the arm 8 is raised or lowered. The under side of the arm 8 is provided with a boss 19, project-ing downwardly between the. two plates constituting the bar 5, and within which boss is suitably mounted a pin 20 projecting above the arm 8. A supporting base 21 for the electrode is seated upon the upper surface of the arm 8 and is pivoted for horizontal movement or substantially horizontal movement upon the pin 20I This base is formed with a cylindrical bearing member 22 for a sleeve 23 within which the electrode 24 is mounted. The arcing face of this electrode when used in a searchlight as indicated in Fig. 3 must be maintained in vthe focus of the reflector 24C', as is well understood in the art. The sleeve 23 is formed with a worm gear 25 on a raised portion of the sleeve, which raised portion has an end bearing on the member 22. A ring or collar 26 surrounds the outer end of the sleeve 23 and engagesthe bearing member 22 and is secured to the sleeve yby screws 27. The electrode 24 -is clamped within the :sleeve .23 by a segmental member 28 pivoted to .the sleeve at 29 and` clamped to it by a bolt 30 engaging an opening in the lug 31 on the member 28 and a screw threaded opening in thfe lug 32 on the sleeve. The sleeve 23 4is rotated by a worn-1 33, which is mounted upon a shaft 34, which, in turn, is mounted inears 35 projecting from the supporting base 21. The worm 33 engages the worm gear 25 on the sleeve 23. The shaft 3i may be rotated by a bar 36 which extends without the casing and is lconnected to the shaft 3i :by a universal joint 37. The supporting base 21 is provided with an outwardly extending lug 3S provided with a pin 39 which engages a screw thread on the sha-ft 9 by the rotation of which the pin and lug 38 are given a 1ongitudinal movement and thesupporting base 21, with the electrode, is turned about the pin 2O as an axis.

The operation of my device is very simple, and is as follows: The electrode 24 is rotatedabout its own axis from the bar 36, through the worm 33 and worm gear 25. Under ordinary circumstances this rotation of the electrode alone may be sui'ficient to cause the electrodes to burn off evenly. It', however, for any reason, the electrodes 4have burned unevenly, the arc may be driven to any point desired on the arcing faces of the electrodes by means of the horizontal movement about the pin 20, which, it will be observed, is perpendicular to the axis of the electrode, or the arc may be driven to any desired point by the vertical movement of the electrode about the shaft 9 as an axis, and in a plane including the axis of the pin 20, or the two movements may be combined.

I have for convenience described the adjustment of the carbon as being made in a horizontal plane and in a vertical plane. It will be understood, of course, that my invention is not limited to the particular position in which the electrodes are located and the planes within which they are movable might be oblique to the horizontal and vertical planes.

In accordance with the 'provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the 4best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

IVhat I claim as new and desire lto secure by .Letters Patent yof the United States, is

1. In an arc lamp, a pair of substantially alined electrodes, -a .support .for one of the electrodes only, means for :rotating said electrode about its axis, .and means `for turning said Velectrode about one or more axes which are perpendicular to the axis et the electrode.

2. In an arc lamp, a support for one of the electrodes only, mea-ns for rotating said electrode about its axis, means for rotating said electrode in a horizontal plane, a-nd means for rotating the same in a vertical plane.

3. In an arc lamp, a support for Vone of the electrodes only, a bearing i-n which one. of the electrodes is mounted having `a pivotal connection with said support, 4means for rotating said electrode about said pivot .as an axis, means for rotating said electrode in a plane including said axis, and means for rotating said electrode about its own axis.

4. In an arc lamp, a support for one of the electrodes only, an arm pivotally mounted thereon, a supporting member lfor one of the electrodes pivotally mounted upon lsaid arm, means for rotating said arm about -ts pivot, means for rotating sai-d supporting member about its pivot, and means for rotating said electrode about its own axis.

5. In an are lamp, a pair of substantially axially alined electrodes, means for rotating one of said electrodes about its own axis, and means for effecting a universal adjustment of the arcing face of said electrode in front of the arcing facev of the other.

6. A projector aro lam-p comprising a casing, an optical element associated therewith, a negative electrode, means for supporting a positive elect-rode in said casing in a substantially horizontal position with its arcingend substantially in the focus of said optical element and comprising an electrode holder and means for adjusting said holder -in two planes at right angles to each other and means for rotating Asaid holder on its axis.

In witness whereof, I have hereunto set my hand this 3d day of July, 1913.

JOHN o. oHNsTAD.

Vitnesses:

M. BEITSCHEY, T. Paume.

Copies of this patent may be obtained for five cents each, by'addrassng the Commissioner of Pate-nts, Washington, D. C. 

